The present invention relates to license management systems and particularly to a method and system for providing flexibility to a license management system.
The licensing of computer software was traditionally accomplished by providing a copy of the software and a license for each computer which was authorized to use the software. The software could be generally used only on that computer, unless it was deleted from that computer and transferred to another one together with the license. With the advent of wide spread computer networks a more efficient solution was required. A license management system allows a user to install a copy of a software program on N nodes of a network, but acquire only a limited number n licenses, where at any time, only the maximum number n copies of that program can be simultaneously run on the network. When all the available licenses are allocated, additional users requesting the use of that software must wait for a license to become available. This kind of license management system has a number of advantages for both the software vendor and the user, because it allows the user to purchase all and only the licenses really needed and, on the other hand, allows the vendor to fight software piracy.
An example of a state of the art license management system available on the market, is the License Use Management product of International Business Machines Corporation.
In a typical network of interconnected computers with a license management system, as illustrated in FIG. 1, one or more of the nodes 101 act as license servers, while a plurality of nodes 103 act as clients of the license servers. The service provided by a license server 101 to its client 103 is that of granting or denying permission to run a given software program, according to the availability of a license record in the license server data base, and to the terms and conditions encoded in the license record itself. The license server usually creates and stores license records in the license data base upon processing license certificate files, which are provided by the software vendor and complement the software program to which they are related. This license data base must be locked in some way to the specific instance of the license server (hardware+software) to prevent malicious users from copying the license data base to another license server machine and multiplying by two the number of licenses for all the software products contained in the license data base. License certificate files may contain some encryption or checksum information that allow the license server to verify their authenticity and integrity.
The fact that a license management system is monitoring the use of a given software program should be as transparent as possible to the users of that software program whereas it should be evident and beneficial to the administrator of licenses for that and other software programs. This consideration places a strong requirement on the license management system in terms of reliability and performance. The ideal license management system should be one which never causes software program failures because of its outage nor becomes a bottleneck for the software programs that it monitors.
In a license management system, xe2x80x9cavailabilityxe2x80x9d is a measure of the degree to which the system can process and satisfy incoming requests (either granting or denying permission to run) within the time limits set by the served environment. High availability systems attempt to provide a continuous service within a particular operational window by minimising causes of failure and minimising recovery time when failures occur. Usually this requires a large degree of redundancy in system components, so that the continued operation of the entire system is protected from failure of any single component. The ultimate objective is to eliminate all single points of failure in the system. This can be accomplished by having redundant components or systems, and xe2x80x9cavailability management technologyxe2x80x9d that can automate the transfer of services to those redundant components when a failure occurs. Availability is a crucial feature of license management systems, since an outage of one or more license servers of a license management system can prevent many users from running their critical applications, due to a failure to acquire a license. An obvious solution to ensure good availability would be to use well known clustering techniques. In the network data processing field, a cluster is a set of independent processors (nodes), connected over the network. A cluster constitutes a sort of xe2x80x9cblack boxxe2x80x9d which provides certain services to end users. Like any ideal black box system, the end users do not need to know which node in the cluster they are connecting to. However, common clustering techniques, aimed at increasing the overall availability of the system through server redundancy, cannot be applied in a straightforward way to license management systems because of the secure nature of the license serving environment. A redundant license server cannot simply take over the amount of licenses, served by another failing server; it must also ensure that, in no circumstances, the total number of licenses concurrently served can exceed the total number of available licenses, stored into the license authorization record.
Solutions to this problem, based on a method called xe2x80x9cmajorityxe2x80x9d or xe2x80x9cquorumxe2x80x9d, are known, in which a certain number of license servers are configured to work cooperatively. As long as the majority of those servers is up and running and communicating with each other, all licenses are available, whereas as soon as the number of active license servers becomes less than the majority, all of the servers stop serving licenses. All existing solutions do not allow flexibility in the number of license servers that participate in the cluster. This number is either fixed by the licensing system vendor or can be chosen upfront by the user when configuring the system, but it is not possible to increase or decrease the number of license servers in the cluster, during the life-cycle of the cluster itself. Having the possibility of adding and removing license servers to and from a cluster is an important feature to ensure the required flexibility for adapting the system capacity to the changing demands of the application environment.
In theory flexibility could be provided, for example, by binding the license authorization key to a software based, random generated, binary identifier that can be securely stored into the license server""s data base instead of binding them (the license key) to some specific license server hardware-based identifier. The same software-based binary identifier can be shared by all license servers participating in the cluster. However providing such a flexibility without any limitations on the way license servers can be added or removed from the cluster breaks the security of the license management system.
It is an object of the present invention to alleviate the above drawbacks of the prior art.
According to the present invention, we provide, in a network comprising a plurality of client workstations having a software program installed thereon, and a cluster comprising an initial plurality of S license servers, a license management system for allowing the concurrent use of a maximum number n of copies of the software program, each client workstation requiring an authorisation from one of the license servers for using the software program, the license management system requiring that at least the integer majority of the plurality of license servers in the cluster is active at any time, the license management system comprising:
means for allowing an increase or decrease in the number of license servers;
means for limiting the number of the plurality of license servers with respect to the initial number S so that the integer majority of the minimum number s1 of servers in the cluster plus the integer majority of the maximum number s2 of servers in the cluster is strictly greater than the maximum number s2 of servers in the cluster.
Furthermore, according to the present invention, we provide a method for providing flexibility to a license management system, the license management system permitting the concurrent use of n copies of a software program over a network comprising a plurality of client workstations, each client workstation having a copy of the software program installed thereon requiring an authorisation from one of a plurality of S license servers each time the software program is used, the license management system requiring that at least the integer majority of the plurality of license servers is active at any time, the method comprising the step of:
allowing an increase or decrease in the number of license servers;
limiting the number of the plurality of license servers with respect to the initial number S so that the integer majority of the minimum number s1 of servers plus the integer majority of the maximum number s2 of servers is strictly greater than the maximum number s2 of servers.
Also according to the present invention we provide a computer program product stored on a computer readable medium for allowing, in a network comprising a plurality of client workstations having a software program installed thereon, and an initial plurality of S license servers, the concurrent use of a maximum number n of copies of the software program, each client workstation requiring an authorisation from one of the license servers before using the software program, the computer program product requiring that at least the integer majority of the plurality of license servers is active at any time, the computer program product comprising:
computer readable program code means for allowing an increase or decrease in the number of license servers;
computer readable program code means for limiting the number of the plurality of license servers with respect to the initial number S so that the integer majority of the minimum number s1 of servers plus the integer majority of the maximum number s2 of servers is strictly greater than the maximum number s2 of servers.